The present invention relates to conveying apparatus for handling relatively large articles, such as automotive body side panels which are conveyed along a production line to a series of work stations.
The vast majority of present day automobiles are of a so called unitized body construction in which the vehicle body is made up of stamped sheet metal components, i.e. roof panel, floor panel, side panels, etc., which are assembled to each other by welding. Particularly in the case of body side panels, additional structural components, such as mounting brackets, door lock and hinge reinforcements, etc. are assembled on to the panel prior to its subsequent assembly to the other components of the vehicle body. The assembly of these additional components to the panel is typically accomplished at a series of work stations disposed along a conveying line which transfers the panels from station to station.
Most, if not all, of these work stations are automated, and automated assembly of this type requires a precise positioning of the panel relative to the automated equipment so that the various parts are precisely located on the panel. Achievement of such alignment and access to the desired locations on the panel by the assembly tooling cannot always be achieved while the panel is supported upon the conveyor, and at the typical work station, a stationary work frame especially designed to support the panel in alignment with the tooling is employed to support the panel while the particular assembly of operation is performed. This in turn involves a transfer of the panel from the conveyor to the work frame to perform the assembly operation and the subsequent transfer of the panel back from the work frame to the conveyor after the operation is completed.
To accomplish such a transfer, a transfer device must be accurately aligned both with the conveyor and with the work frame upon which the body panel is positioned in alignment with the automated tooling. In that the typical conveyor will extend for one hundred feet or more and pass several work stations, precise alignment of all portions of the conveying path with a fixed reference point is difficult to achieve in practice. In so far as the path of movement of parts or panels along the conveyor is concerned, precise positioning is of little concern during transit of the panels between successive work stations. However, at arrival at a work station, the panel must be precisely positioned relative to the transfer mechanism which in turn must be precisely positioned relative to the work frame.
The present invention is directed to a transfer device or manipulator for transferring a panel from the conveying path to and from a stationary work frame at a work station which assures placement of the panel on the stationary work frame within the desired degree of precision by means of a relatively simple self aligning mechanism.